Thermally insulated transfer line

ABSTRACT

A thermally insulated transfer line for a deep-cooled fluid. The thermally insulated transfer line includes a process line for conduction of the deep-cooled fluid, an insulation envelope lying radially outside the process line and extending in a longitudinal direction of the process line, and an insulation space between the process line and the insulation envelope. The process line and the insulation envelope, at least in portions along a length in a longitudinal direction of the thermally insulated transfer line, have a U-shape, or a V-shape, or meandering form, or a helical form.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority 35 U.S.C. § 119 to EuropeanPatent Publication No. EP 22158910.4 (filed on Feb. 22, 2022), which ishereby incorporated by reference in its entirety.

TECHNICAL FIELD

Embodiments relate to a thermally insulated transfer line for adeep-cooled fluid, in particular, a transfer line for connection to acryogenic tank.

BACKGROUND

Cryogenic tanks for storing deep-cooled fluids, in particular, forstoring hydrogen, are well known. Cryogenic tanks may also be used inmobile installations, for example, for transporting fuel in vehicles andaircraft. In order to transfer the stored medium of a cryogenic tank,for example, into another cryogenic tank, transfer lines may be usedwhich may consist of two concentric pipelines with a vacuum between thepipelines. Such transfer lines are normally used for static applicationsand are not suitable for absorbing dynamic loads. Owing to their rigidconstruction mode which is a result of the necessity of asuperinsulation with a vacuum and, for example, a multi-layer insulation(MLI) between two pipelines, axial and rotary forces acting on the linecannot be readily absorbed. Movements in the longitudinal direction, orflexural movements, can indeed be compensated for by the use of bellows,but bellows have disadvantages such as, for example, a low mechanicalload-bearing capability and the fact that said bellows are incapable ofabsorbing high torsional moments and associated twisting. Therefore, theknown solutions are barely suitable for mobile applications of transferlines.

SUMMARY

Embodiments are operable to enhance thermally insulated transfer linesof said type in this respect, and in particular, to provide a thermallyinsulated transfer line which is suitable for mobile applications and isalso able in particular, to effectively absorb axial forces and/ortorsion moments.

Embodiments relate to a thermally insulated transfer line for adeep-cooled fluid, comprising a radially inner process line forconduction of the fluid, a preferably concentric insulation envelopelying radially outside the process line and running in the longitudinaldirection of the process line, wherein an insulation space, for examplea vacuum space, is formed between the process line and the insulationenvelope, wherein the process line and the insulation envelope together,at least in portions along their extent in the longitudinal direction ofthe transfer line, have a U-shape or a V-shape or a meandering form or ahelical form.

In accordance with embodiments, a transfer line, more precisely, boththe process line directly conducting the fluid and the insulationenvelope surrounding the process line, have a U-shape or a V-shape or ameandering form or a helical form along their longitudinal direction.Here, a “U-shape” or “V-shape” means that one, preferably more, at leasttwo, U-shaped or V-shaped protrusions are provided axially one behindthe other. The U-shape, V-shape, meandering and helical forms may bemore rounded, i.e., as bends, or also more angular, e.g. as corners.Instead of a linear connection between the start and end of the processline and insulation envelope, thus bulges are provided which must thenturn back in. Thus a longer line length may be obtained which is formedtwo-dimensionally, e.g. as a meander or U-shape or V-shape, orthree-dimensionally so that adjacent meanders or U-shapes or V-shapesare twisted relative to one another and/or form a helix, in order to beable to better absorb axial forces and/or torsion moments. Thus forexample, relative movements between two tanks connected by the transferline, in particular, torsional and/or axial movements, can be betterabsorbed in the transfer line. The transfer line is therefore preferablypreformed, preferably substantially as a meander or helix, e.g. forms aspring, in particular, a cylinder spring.

Preferably, the process line at least in portions is a corrugated tubeor corrugated hose, and particularly preferably, the insulation envelopeis also at least in portions a corrugated tube or corrugated hose.

The insulation envelope may also be concentrically surrounded by furtherinsulation envelopes, which may again each be formed as corrugated tubesor corrugated hoses, so that in each case insulation spaces, e.g. vacuumspaces, are formed between the insulation envelopes.

Preferably, the process line and the insulation envelope together, atleast substantially over the entire extent in the longitudinal directionof the transfer line, have a U-shape or a V-shape or a meandering formor a helical form, or over at least 40%, preferably at least 60%,particularly preferably at least 80% of their extent in the longitudinaldirection of the transfer line. Preferably, the entire transfer line, atleast the process line, insulation envelope and insulation spacearranged in between, has the U-shape or V-shape or meandering form orhelical form over the entire length, apart from the connection orcoupling regions at the ends of the transfer lines. As stated, the“U-shape” or “V-shape” means that preferably several U-shaped orV-shaped protrusions are provided axially one behind the other to formthe given extent region.

Preferably, the process line and the insulation envelope are arrangedconcentrically to one another, wherein the concentricity also existsalong the portions along the extent of the transfer line in thelongitudinal direction which have a U-shape or V-shape or meanderingform or helical form.

Preferably, spacers are provided between the process line and theinsulation envelope for ensuring a distance between the process line andthe insulation envelope, also along the portions along the extent of thetransfer line in the longitudinal direction which have a U-shape orV-shape or meandering form or helical form.

Preferably, provided in the insulation space is a vacuum and/or a solidinsulation, and/or an inert gas such as CO₂, and/or a thermallyreflective layer, for example, a Multilayer Insulation (MLI). The inertgas is a gas which has a high setting point, in any case higher thanthat of air, and/or a triple point higher than the condensationtemperature of oxygen. The solid insulation uses at least one or morethermally poorly conductive solids, either mixed or arranged in layers.A thermally reflective layer is a layer which reduces thermal transferby radiation.

Preferably, in the insulation space, in portions an absorbent materialis arranged, in particular, zeolite, active charcoal and/or getter, forexample, barium.

Preferably, a protective envelope runs along the extent of theinsulation envelope, radially outside the insulation envelope, whereinpreferably the protective envelope does not have the U-shape or V-shapeor meandering form or helical form, wherein the protective envelopeparticularly preferably has a cylinder casing form, i.e. flat walls. Thethermally insulated cryogenic line, preferably in the form of a“cylinder spring”, is thus preferably conducted between two tanks bymeans of an external protective tube.

Preferably, at least in portions, a damping material and/or an elasticmaterial is arranged between the protective envelope and the insulationenvelope, for example on the inside of the protective envelope or on theoutside of the insulation envelope or in the entire intermediate space.The damping material and/or elastic material may serve to dampvibrations and/or to support the preformed, in particular, helicallines, and for protection at the contact points of the insulationenvelope and protective envelope.

Preferably, the protective envelope comprises at least two envelopesections which are movable axially relative to one another, wherein theenvelope sections are preferably connected together by a bellows and/ora bush and/or a sleeve, and/or are radially nested so that one envelopesection can slide radially inside or outside the other envelope sectionin an overlap portion. A length compensation for the protective envelopeis thus possible.

Preferably, a coupling element is provided at least at one end of thetransfer line, preferably at both ends of the transfer line, forconnecting the transfer line to a cryogenic tank in a fluid-conductivemanner.

The coupling element preferably comprises a union nut which isconfigured such that the process line of the transfer line is attachedto a tank process line such that a fluid-conductive connection iscreated between the process line and the tank process line. The unionnut preferably attaches an end sleeve of the process line to the tankprocess line.

Preferably, the coupling element comprises an end piece, wherein theinsulation envelope of the transfer line transforms into the end piece.The end piece is not configured here as a corrugated tube or corrugatedhose, but is mechanically firm.

Preferably, the coupling element comprises a connecting sleeve, whereinthe connecting sleeve is arranged concentrically to and radially on theoutside of the end piece, and is attached to the end piece, preferablywelded to the end piece, wherein the attachment or welding preferablytakes place at an axial end of the connecting sleeve which faces theinsulation envelope, i.e. faces away from the tank to be coupled. Withsuch a connecting sleeve, the thermal resistance can be increaseddespite the compact construction.

Preferably, the coupling element has a sliding coupling sleeve, whereinthe sliding coupling sleeve is arranged concentrically radially on theoutside of the end piece and/or the connecting sleeve and is axiallymovable relative to the end piece and/or the connecting sleeve.Particularly preferably, the sliding coupling sleeve lies radiallyoutside the connecting sleeve, in a region in which the end piece of theinsulation envelope also runs radially inside the connecting sleeve, andagain the process line runs radially inside the insulation envelope. Thesliding coupling sleeve is movable axially relative to the connectingsleeve. The sliding coupling sleeve preferably, at its axial end facingaway from the insulation envelope, has a flange surface for connectionto a connecting flange of the component to be coupled, in particular,the tank.

Preferably, a nut is arranged concentrically radially on the outside ofthe connecting sleeve and is configured to push the sliding couplingsleeve axially against a stop of the connecting sleeve and/or axiallyagainst a connecting flange of the cryogenic tank.

Preferably, the end piece, in an axial portion in which the end piece issurrounded by the connecting sleeve, is at least partially formed by abellows. With such a bellows, the thermal resistance can be increasedfurther despite the compact construction. Also, a compensation forcomponent tolerances is thus possible, and the contact force of theprocess line on a tank process line of the component to be coupled canalso be increased.

The connecting sleeve weld point, i.e. the weld point of the connectingsleeve and end piece, is preferably formed on the end piece axiallybetween the bellows and the insulation envelope.

Preferably, the end piece comprises a vacuum connector, wherein via thevacuum connector, a vacuum can be created in the insulation space or theinsulation space can be flooded with an inert gas.

Preferably, the end piece has a coupling space vacuum connector, whereinvia the coupling space vacuum connector, a vacuum can be created in thecoupling space or the coupling space can be flooded with an inert gas.

Preferably, inside the end piece, an absorbent material is arranged, inparticular, zeolite, active charcoal and/or getter, for example barium.

DRAWINGS

Embodiments will be illustrated by way of example in the drawings andexplained in the description hereinbelow.

FIG. 1 illustrates a front, sectional view of a thermally insulatedtransfer line, in accordance with one or more embodiments.

FIG. 2 illustrates a sectional view of a transfer line along section A-Aof FIG. 1 .

FIG. 3 illustrates a sectional view of another transfer line alongsection A-A of FIG. 1 .

FIG. 4 illustrates a sectional view of a further transfer line alongsection A-A of FIG. 1 .

FIG. 5 illustrates a sectional view of a coupling element at one end ofa transfer line in open state, in accordance with one or moreembodiments.

FIG. 6 illustrates a sectional view of a coupling element at one end ofthe transfer line of FIG. 5 , in a connected state.

FIGS. 7A through 7C illustrate sectional views of the coupling elementof FIG. 5 in process steps on connection of the coupling element.

DESCRIPTION

FIG. 1 illustrates a front, sectional view from the front of a thermallyinsulated transfer line, in accordance with one or more embodiments. Thetransfer line comprises a radially inner process line 1 for conducting afluid, in particular, hydrogen, and an insulation envelope 2 lyingradially outside the process line 1, extending over the entire length ofthe process line 1 and concentric to the process line 1. An insulationspace 3 is provided between the process line 1 and the insulationenvelope 2. The process line 1, the insulation envelope 2, and theinsulation space 3 have a helical form in the longitudinal direction ofthe transfer line, as indicated in FIG. 1 .

FIG. 1 furthermore shows a protective envelope 4 which is arrangedradially outside the insulation envelope 2 and extends substantially inthe longitudinal direction of the process line 1 and the insulationenvelope 2. The protective envelope 4 does not have a helical form butis formed flat, and thus, has a cylinder casing form.

FIGS. 2 through 4 illustrate a side view of the thermally insulatedtransfer line of FIG. 1 , corresponding to section A-A from FIG. 1 .FIG., 2 however, illustrates or provides no protective envelope. FIG. 3illustrates or provides, in addition to the process line 1 andinsulation envelope 2, coupling elements 6 at both ends of the transferline. FIG. 4 also illustrates or provides a protective envelope 4, as inFIG. 1 , extending over the entire length of the transfer line.

In accordance with one or more embodiments, the innermost element of thethermally insulated transfer line is the process line 1, in particular,a corrugated pipe in which the deep-cooled fluid is transported. Theprocess line 1 is surrounded by one or more concentric corrugated hoses,namely insulation envelopes 2, each of which is thermally insulated byan insulation space 3 and optional MLI from the respective nextinnermost corrugated hose. The distance between the process line 1 andthe insulation envelope 2 is guaranteed by a suitable device, e.g.spacers, which may, for example, extend in the longitudinal direction ofthe thermally insulated transfer line. In addition, absorption means maybe placed in the insulation space 3 to enhance the long-term stabilityof the vacuum. The ends of the transfer line are terminated withcorresponding fittings or connections, in particular, the couplingelements 6.

For protection and guidance, the process line is conducted, for example,between two tanks inside an external envelope tube, namely theprotective envelope 4, as shown in FIG. 4 . This tube forming theprotective envelope 4 serves mainly for protection against stone impact,weathering, and corrosion, but also secures the vacuum line againsttouch and associated risks from the very low temperatures. The externalenvelope tube, or protective envelope 4, is also used for safe mountingand as a damping element. The damping is achieved by direct pressing ofthe vacuum line formed by the process line 1 and the insulation envelope2 which may be sheathed with plastic, against the external corrugatedtube, and prevents damage by modulation of frequency and minimizing ofthe vibration amplitude.

The protective envelope 4 comprises at least two envelope sections 4.1,4.2 which are axially movable relative to one another. The envelopesections 4.1, 4.2 are connected together by a bellows 5 and radiallynested, so that one envelope section 4.1 can be axially moved radiallyinside or outside the other envelope section 4.2 in an overlap portion.At least at one end, in the embodiment shown in FIGS. 3 and 4 , at bothends, the transfer line has coupling elements 6 which are shown in moredetail in FIGS. 5 and 6 .

A coupling element 6 comprises the following parts (see FIG. 5 ): theinsulation envelope 2 transforms into a mechanically firm end piece 9.The process line 1 also has a firm sleeve at its end, namely the endsleeve 24, which is welded to the end piece 9 at an end piece weld point18. The coupling element 6 allows an increase in thermal conductionresistance with a compact structure of the end piece of the transferline. The process line 1 and the insulation envelope 2 are weldedtightly in the end piece, namely the coupling element 6, as describedabove, and this weld point 18 constitutes a good thermal connection. Inorder to reduce the heat transfer into the deep-cooled fluid along theinsulation envelope 2 of the end piece, and to avoid temperatures belowthe liquefaction point of oxygen at the insulation sleeve 2 of the endpiece, the thermal resistance to thermal conductivity in the insulationenvelope 2 of the end piece coupling element 6 is increased. For apredefined material, e.g. steel, the resistance can be increased bygeometry adaptation, in particular, by a small cross-section and longconduction path (the heat transfer path is drawn as an arrow in FIG. 6).

A preferably thin-walled bellows 15 forms a portion of the end piece 9and increases the thermal resistance by extension of the conduction pathbecause of the corrugated form. A connecting sleeve 10 increases thethermal resistance by extending the conduction path because of the weldconnection 19 to the end piece 9 which is offset in the direction of thevacuum connector 16.

The mounting of the coupling element and the compensation of mountingtolerances to guarantee the required contact forces of the seals isdescribed below, see also FIG. 6 .

The process line 1 and insulation envelope 2 must be tightly connectedto the tank/dewar comprising the tank process line 8 and connectingflange 14. Firstly, the two process lines 8, 1 are butt-connected via aunion nut 7. By tightening the union nut 7, a process line seal 20 iscompressed at the end between the pipe ends. Access for mounting theprocess line 1 is possible by sliding back a sliding coupling sleeve 11which slides on the connecting sleeve 10. After connecting the processlines 1, 8, the sliding coupling sleeve 11 is fixed with a nut 12against the sealing face 13 on the connecting sleeve 10, in particular,at a stop of the connecting sleeve 10. A flange of the sliding couplingsleeve 11 is pressed against the connecting flange 14 of the tank/dewar,and hence, the transfer line of the tank/dewar is pressed. The opposingforces are shown as arrows in FIG. 6 . As a result, the (required)contact forces of the process line seal 20 between the process lines 1,8, and/or the connecting sleeve seal 13 between the connecting sleeve 10and sliding coupling sleeve 11, and the connecting flange seal 21between the sliding coupling sleeve 11, or more precisely the flangeface 22 of the sliding coupling sleeve 11, and the connecting flange 14of the tank/dewar are reduced, and the sealing effect is lessened. Thebellows 15 in the end piece 9 partially compensates for this loss ofcontact force. The position of the bellows 15 in the end piece 9 reducesthe loading with torsion and bending moments.

Thus, the connecting sleeve 10 serves to increase the thermal resistancedespite the compact construction; the bellows 15 serves to increase thethermal resistance despite the compact construction, to compensate formounting tolerances and to guarantee adequate contact force for thesealing effect; and the sliding coupling sleeve 11 allows access to theprocess lines 1, 8 and forms a connection, namely at a coupling spacevacuum connector 23, for evacuating the coupling space or rendering thisinert.

FIGS. 7A through 7C illustrate steps in connecting the coupling element6 to a tank and the possibility of quickly and easily rendering thecoupling space inert.

FIG. 7A shows how the coupling element 6 is brought up to the tank inorder to connect the process line 1 to the tank process line 8 (in thedirection of the arrow).

In FIG. 7B, the union nut 7 is already closed around the process lines1, 8, and the sliding coupling sleeve 11 is moved in the directiontowards the tank (arrow) where it is connected to the connecting flange14 by means of the nut 12.

FIG. 7C shows the connected coupling element 6 with connected union nut7 and nut 12, so that the coupling space can be evacuated or renderedinert via the coupling space vacuum connector 23. After connection ofthe coupling, therefore, via the coupling space vacuum connector 23, atthe sliding coupling sleeve 11, the relatively small coupling spaceseparated from the transfer line and tank can rapidly and easily beevacuated or rendered inert with an inert gas with sufficiently highsetting point.

The terms “coupled,” “attached,” or “connected” may be used herein torefer to any type of relationship, direct or indirect, between thecomponents in question, and may apply to electrical, mechanical, fluid,optical, electromagnetic, electromechanical, or other connections. Inaddition, the terms “first,” “second,” etc. are used herein only tofacilitate discussion, and carry no particular temporal or chronologicalsignificance unless otherwise indicated.

Those skilled in the art will appreciate from the foregoing descriptionthat the broad techniques of the embodiments can be implemented in avariety of forms. Therefore, while the embodiments have been describedin connection with particular examples thereof, the true scope of theembodiments should not be so limited since other modifications willbecome apparent to the skilled practitioner upon a study of thedrawings, specification, and following claims.

LIST OF REFERENCE SYMBOLS

-   -   1 Process line    -   2 Insulation envelope    -   3 Insulation space    -   4 Protective envelope    -   4.1 Envelope section    -   4.2 Envelope section    -   5 Bellows    -   6 Coupling element    -   7 Union nut    -   8 Tank process line    -   9 End piece    -   10 Connecting sleeve    -   11 Sliding coupling sleeve    -   12 Nut    -   13 Stop of connecting sleeve, seal of connecting sleeve    -   14 Connection flange    -   15 Bellows    -   16 Vacuum connector    -   17 Absorbent material    -   18 End piece weld point    -   19 Connecting sleeve weld point    -   20 Process line seal    -   21 Connecting flange seal    -   22 Flange surface    -   23 Coupling space vacuum connector    -   24 End sleeve

What is claimed is:
 1. A thermally insulated transfer line for adeep-cooled fluid, the thermally insulated transfer line comprising: aprocess line for conduction of the deep-cooled fluid; an insulationenvelope lying radially outside the process line and extending in alongitudinal direction of the process line; and an insulation spacebetween the process line and the insulation envelope; wherein theprocess line and the insulation envelope, at least in portions along alength in a longitudinal direction of the thermally insulated transferline, have a U-shape, or a V-shape, or a meandering form, or a helicalform.
 2. The thermally insulated transfer line of claim 1, wherein: theprocess line, at least in portions thereof, comprises a corrugated tube,and/or the insulation envelope, at least in portions thereof, comprisesis a corrugated tube.
 3. The thermally insulated transfer line of claim1, wherein the process line and the insulation envelope are arrangedconcentrically to one another.
 4. The thermally insulated transfer lineof claim 1, further comprising spacers arranged between the process lineand the insulation envelope to maintain a distance between the processline and the insulation envelope.
 5. The thermally insulated transferline of claim 1, further comprising a vacuum arranged in the insulationspace.
 6. The thermally insulated transfer line of claim 1, furthercomprising an absorbent material arranged in portions of the insulationspace.
 7. The thermally insulated transfer line of claim 1, furthercomprising solid insulation arranged in the insulation space.
 8. Thethermally insulated transfer line of claim 1, further comprising aninert gas arranged in the insulation space.
 9. The thermally insulatedtransfer line of claim 1, further comprising a thermally reflectivelayer arranged in the insulation space.
 10. The thermally insulatedtransfer line of claim 1, further comprising a protective envelope,formed as a cylinder casing, extending radially outside along a lengthof the insulation envelope.
 11. The thermally insulated transfer line ofclaim 10, further comprising a damping material and/or an elasticmaterial arranged between the protective envelope and the insulationenvelope.
 12. The thermally insulated transfer line of claim 10, whereinthe protective envelope comprises at least two protective envelopesections that are connected to each other in a manner that enablesaxially movable relative to one another, the at least two protectiveenvelope sections being radially nested to enable one protectiveenvelope section to slide radially inside or outside another protectiveenvelope section in an overlap portion.
 13. The thermally insulatedtransfer line of claim 1, further comprising a coupling element arrangedat both ends of the thermally insulated transfer line to connect thethermally insulated transfer line to a cryogenic tank.
 14. The thermallyinsulated transfer line of claim 13, wherein the coupling elementcomprises a union nut which is configured such that the process line isattached to a cryogenic tank process line to establish afluid-conductive connection between the process line and the cryogenictank process line.
 15. The thermally insulated transfer line of claim13, wherein: the coupling element comprises an end piece, and theinsulation envelope of the transfer line transforms into the end piece.16. The thermally insulated transfer line of claim 15, wherein thecoupling element comprises a connecting sleeve arranged concentricallyto and radially on an outside surface of the end piece for connection tothe end piece.
 17. The thermally insulated transfer line of claim 15,wherein: the coupling element comprises a sliding coupling sleevearranged concentrically radially on an outside of the end piece, and/orthe connecting sleeve and is axially movable relative to the end pieceand/or the connecting sleeve, and a nut is arranged concentricallyradially on the outside of the connecting sleeve to push the slidingcoupling sleeve axially against a stop of the connecting sleeve and/oraxially against a connecting flange of the cryogenic tank.
 18. Thethermally insulated transfer line of claim 15, wherein the end piece, inan axial portion in which the end piece is surrounded by the connectingsleeve, is at least partially formed by a bellows.
 19. The thermallyinsulated transfer line of claim 15, wherein the end piece comprises avacuum connector to establish a vacuum in the insulation space.
 20. Athermally insulated transfer line for a deep-cooled fluid, the thermallyinsulated transfer line comprising: a process line for conduction of thedeep-cooled fluid; an insulation envelope lying radially outside theprocess line and extending in a longitudinal direction of the processline; and an insulation space arranged between the process line and theinsulation envelope, wherein the process line and the insulationenvelope, at least 80% of an entire length in a longitudinal directionof the thermally insulated transfer line, have a meandering form or ahelical form.